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3 years ago

Why is hydroelectric power considered to be an example of multiple transfers of energy?

1 answer:

7 0

Hydroelectric power is considered to be an example of multiple transfers of energy because potential energy when the water is in the reservoir turns into kinetic energy making the water move to the dam and then the dam moves into the turbine turning it to electric energy.

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A diamond is cut such that the angle between its top surface and its bottom surface is α. For α=45∘, find the largest possible v

Reil [10]

Answer:

i = 61 degree

Explanation:

Given,

$\alpha =45^{o}$

Now, by the snell's law

$sin\theta_c=\frac{1}{n}\\sin\theta_c=\frac{1}{2.450}\\\theta_c=24.09^o$

Now,

Sin i / sin r = n 2 / n 1

sin i / sin r (45 - 24.09) = 2.45 / 1

i = 60.97 degree

4 0

4 years ago

Why do scientists conduct experiments ?

kkurt [141]

Scientists conduct experiments in order to prove a theory or a prediction they have or contradict it, so that then they can write down their results to study them.

8 0

4 years ago

2.) The lob in tennis is an effective tactic when your opponent is near the net. It consists of lofting the ball over his/her he

Ratling [72]

Answer:

The minimum average speed the opponent must move so that he is in position to hit the ball is approximately 5.79 m/s

Explanation:

The given parameters of the ball are;

The initial speed of the ball = 15 m/s

The direction in which the ball is launched = 50° above the horizontal

The location of the other tennis player when the ball is launched = 10 m from the ball

The time at which the other tennis player begins to run = 0.3 seconds after the ball is launched

The height at which the ball is hit back = 2.1 m above the height from which the ball is launched

The vertical position, 'y', at time, 't', of a projectile motion is given as follows;

y = (u·sinθ)·t - 1/2·g·t²

When y = 2.1 m, we have;

2.1 = (15·sin(50°))·t - 1/2·9.8·t²

∴ 4.9·t² - (15·sin(50°))·t + 2.1 = 0

Solving with the aid of a graphing calculator function, we get;

t = 0.199776187257 s or t = 2.14525782198 s

Therefore, the ball is at 2.1 m above the start point on the other side of the court at t ≈ 2.145 seconds

The horizontal distance, 'x', the ball travels at t ≈ 2.145 seconds is given as follows;

x = u × cos(50°) × t = 15 × cos(50°) × 2.145 ≈ 20.682 m

The horizontal distance the ball travels at t ≈ 2.145 seconds, x ≈ 20.682 m

Therefore, we have;

The time the other player has to reach the ball, t₂ =2.145 s - 0.3 s ≈ 1.845 s

The distance the other player has to run, d = 20.682 m - 10 m = 10.682 m

The minimum average speed the other player has to move with, $v_s$ = d/t₂

∴ $v_s$ = 10.682 m/(1.845 s) ≈ 5.78970189702 m/s ≈ 5.79 m/s

The minimum average speed the opponent must move so that he is in position to hit the ball, $v_s$ ≈ 5.79 m/s.

5 0

3 years ago

A mass m is attached to a string connected to a force sensor on a rotating platform. The platform’s angular velocity, ω, can be

makkiz [27]

Answer:

The mass m is 0.332 kg or 332 gm

Explanation:

Given

The platform is rotating with angular speed , $\omega =8.5\, \frac{rad}{sec}$

Mass m is moving on platform in a circle with radius , $r=0.20\, m$

Force sensor reading to which spring is attached , $F=4.8\, N$

Now for the mass m to move in circle the required centripetal force is given by $F=m\omega ^{2}r$

=> $4.8=m\times 8.5 ^{2}\times 0.20$

$=>m=0.332\, kg$

Thus the mass m is 0.332 kg or 332 gm

7 0

3 years ago

A spring that has a spring constant of 1400 N/m is stretched to a length of 2.5 m. If the normal length of the spring is 1.0 m,

Elena L [17]

The answer is C. 1575 J. I just took this review.

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4 years ago

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